1. Field of the invention
The present invention relates to a cardiovascular prosthesis with excellent patency or biocompatibility, especially a vascular graft of medium or small diameter, and a method of producing the same.
2. Description of the Prior Art
Vascular surgeries are performed to reconstruct or repair damaged vessels by replacing the damaged portions with vascular grafts or other prostheses. There have been a number of developments aiming at the replacement of the damaged areas by using suitable conduits or making bypaths beyond the damaged areas or reconstruction a new route where no neutral vessels previously existed.
The critical problem facing patients and surgeons alike is to find a suitable conduit. Key to the success for being acceptable by patient body has been found that the implanted material should have pertinent porous structure to help the ingrowth of endothelial cells. Accordingly, vascular protheses made of flexible materials with porous structures have been used. Porousness is usually expressed by water permeability at a certain condition.
Porous structure of the graft accelerates the formation of a thin blood coagulanting layer along the inner surface of the graft, and helps the ingrowth of the endothelial cells. Generally, favorable dimension of the porous structure ranges between 1.mu. and 100.mu..
So far, fabric or woven conduit made of polyethylene terephthalate or expanded polytetrafluoroethylene (EPTFE) tube have met these requirements have been practically used worldwide for this purpose.